We have previously suggested that the gal operon of E. coli has two promoters. We have obtained additional evidence showing that (1) both the promoters are inducible by galactose; (2) one promoter is activated by cyclic AMP and its receptor protein, the other becoming active only in the absence of the cyclic nucleotide or the receptor protein; and (3) operator constitutive mutations can affect the expression of either or both the promoters. We have previously isolated mutants, defective in transcription termination factor Rho, which are conditional lethal for growth. Further characterization of these mutants have revealed that (1) Rho and RNA polymerase interact for transcription termination, consistent with our previously proposed model, and (2) the rho mutation has pleiotropic effect. We have also extended our study on the antitermination role of gene N of phage lambda and P22, the effect of lambda development on host cell physiology, and pattern of lambda transcripts obtained after infection of several mutant hosts. BIBLIOGRAPHIC REFERENCES: Shapiro, J., Adhya, S. and Bukhari, A.: Introduction to DNA Insertion Elements, Episomes and Plasmids, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, in press 1977. Adhya, S., Gottesman, M. and Court, D.: Independence of gene N and Tof functions of bacteriophage lambda. J. Mol. Biol., in press, 1977.